Marriage equality advocates are engaging in heated debates over the new book about the Prop. 8 fight Forcing the Spring: Inside the Fight for Marriage Equality. Some activists argue the book mythologizes Chad Griffin, co-founder of the American Foundation for Equal Rights, which hired winning attorneys Ted Olson and David Boies—at the expense of all the marriage activism that preceded that May 2009 federal constitutional challenge, including protests by the Gay Activist Alliance after Stonewall, early arguments by conservative gay Andrew Sullivan and coverage of the 1993 Hawaii court case by Michelangelo Signorile.

But the real revelation is that Charles J. Cooper, the conservative attorney for ProtectMarriage.com, has a lesbian daughter who came out to him during the Prop. 8 arguments. They kept it quiet then, but now he’s planning his daughter’s wedding to another woman.

According to journalist Jo Becker Ashley, Ashley Lininger and her partner, only identified as Casey, got engaged in Dec. 2012, just after the Supreme Court decided to take the Prop. 8 and Windsor (DOMA) cases. Cooper argued the case in March 2013.

Becker writes that Cooper and Lininger disagreed over Cooper’s Prop. 8 argument, that states have the right to define marriage as only between one man and one woman and thus intentionally exempting and discriminating against same-sex couples.

“I think the most upset I got was being called an ‘experiment’ that people deserved to see the outcome of before accepting,” Becker quoted Lininger as saying. “It just made me feel … alien, I guess.”

That “experiment” comment came after Cooper was pummeled for his reaction to U.S. District Judge Vaughn Walker when Walker asked him how the state’s interest would be harmed if same-sex couples were allowed to marry. Cooper paused, then stammered, “Your honor, my answer is, I don’t know. I don’t know.” What he meant by that, Cooper said, trying to recuperate, was that same-sex marriage is still so new, it’s “an experiment” the outcome of which is impossible to know.

Lininger, Cooper’s daughter through marriage, lives with her fianc Casey in Massachusetts, the first state to legalize same-sex marriage in 2004. Cooper would not tell Becker how he would vote on the marriage issue. “What I will say only is that my views evolve on issues of this kind the same way as other people’s do, and how I view this down the road may not be the way I view it now, or how I viewed it 10 years ago,” Cooper said.

“My family is typical of families all across America. We love each other; we stand up for each other; and we pray for, and rejoice in, each other’s happiness. My daughter Ashley’s path in life has led her to happiness with a lovely young woman named Casey, and our family and Casey’s family are looking forward to celebrating their marriage in just a few weeks.”

He added: “As Becker reports in her book, I told Ashley that what matters most is that I love her and she loves me.”

It will be interesting to see if Cooper takes up any other anti-marriage equality cases. Prop. 8 strategist Frank Schubert, who has a lesbian sister in a domestic partnrship with another women with whom she is raising children, continues to make fighting LGBT equality his mission in life.